A Multi-Pollutant Strategy


An integrated approach could prove more effective for controlling emissions.

An integrated approach could prove more effective for controlling emissions.

Fortnightly Magazine - January 2009

At this juncture, it is no longer clear exactly what requirements are going to govern further major emission reductions in the electric power sector. EPA promulgated the Clean Air Interstate Rule (CAIR), Clean Air Mercury Rule (CAMR) and Clean Air Visibility Rule (CAVR) in the first half of 2005. The years leading up to these regulations were marked by interplay between two major control paradigms: the traditional, problem-oriented one-issue-at-a-time approach and the more holistic sector-based, multi-pollutant approach. EPA effectively has been on both tracks for the last fourteen years, pursuing problem-oriented solutions while applying lessons learned to broader efforts. With the passage of the CAIR/CAMR/CAVR, EPA was able to achieve a significant first: coordinated multi-pollutant regulations. However, the first two of these rules were derailed when the United States Court of Appeals for the District of Columbia Circuit vacated both CAIR and CAMR earlier this year, throwing the immediate future of power-sector emission reductions into question.

What is not in question is that further emission reductions of SO 2 and NOx, as well as reductions of mercury and possibly carbon dioxide (CO 2), must occur in the power sector to address health and environmental impacts of air pollution as required by the Clean Air Act (CAA) and that power-sector reductions can be cost effective. There is a legitimate sense of urgency to clarify the outlook for further emission reductions. A look at related efforts over the last 14 years provides perspective on the enduring allure of integrating requirements into a market-based multi-pollutant control strategy, and perhaps some insights into two persistent questions: Why hasn’t a deal been reached yet? And why keep trying?

The latest data indicate that 141 million people in the United States live in counties that do not meet the national standards for fine particles and ozone. 1 Electric power generation remains a significant source of nationwide SO 2, NOx and mercury emissions, and related widespread human health and environmental impacts, including premature mortality, heart attacks, hospitalizations and neurological damage in fetuses and young children. In 2007, power generation was responsible for 71 percent of all SO 2 emissions, 22 percent of NOx emissions, and 44 percent of anthropogenic mercury emissions. The power sector also was responsible for 39 percent of anthropogenic CO 2 emissions (see Figure 1).

In the last eleven years, EPA has enacted two rounds of National Ambient Air Quality Standards (NAAQS) revisions for fine particles and ozone to keep pace with emerging science. These efforts commonly found the electric power sector to be both a major contributor of emissions and the source of some of the most cost-effective controls to reduce emissions. EPA obtained similar findings in the related regional haze efforts. Further, the Mercury Report to Congress in December 1997 (and subsequent updates) identified coal-fired utility boilers as